Question

I have an app which is like reading a book, and while reading if user hit home button on iPhone, and again reopen the app , it should open on the same page in which user was previously, i have got x position for all the page, since book is in vertical scrolling. plz let me know where to implement the information.

-(void)scrollViewDidEndDecelerating:(UIScrollView *)_scrollView {
    CGPoint p = _scrollView.contentOffset;
    NSLog(@"x = %f",p.x);
    AppDelegate_iPhone *delegate = [[UIApplication sharedApplication] delegate];
    delegate.dataValue = p.x;
}

Answer 1

You can use NSUserDefaults to save state information.

-(void)scrollViewDidEndDecelerating:(UIScrollView *)_scrollView {
    CGPoint p = _scrollView.contentOffset;
    NSLog(@"x = %f",p.x);
    AppDelegate_iPhone *delegate = [[UIApplication sharedApplication] delegate];
    delegate.dataValue = p.x;

    // save state
    NSUserDefaults* ud = [NSUserDefaults standardUserDefaults];
    [ud setInteger: p.x forKey @"x-position"];
    [ud synchronize];
}

to retrieve saved state

NSUserDefaults* ud = [NSUserDefaults standardUserDefaults];
int x = [ud integerForKey: @"x-position"];